Pivotal rotary screen support and continuous drive therefor

ABSTRACT

A screen printing machine is provided which includes a frame, a backing member supported by the frame, and at least one rotary screen assembly carried by the frame. Each rotary screen assembly is pivotally supported by the frame and includes an inner elongated support member, an outer hollow screen rotatably supported about the inner elongated support member for rotation thereabout, and an elongated applicator, which may be a conventional squeegee, which engages the inner surface of the hollow screen and which is supported by the inner elongated support member located within the screen. A first drive is provided which is operatively connected with the backing member and the rotary screen assembly for rotating the backing member and the outer hollow screen. In accordance with the invention, a second drive is provided for rotating the hollow screen independently of the first drive and the backing member when the screen assembly is moved away from printing engagement with the backing member about the pivoted support. The second drive is selectively operable upon deactivation of the first drive so that the hollow screen of the rotary screen assembly can be rotated after the first drive is deactivated and rotation of the backing member has stopped. In this manner, ink carried in the rotary screen assembly will be continually agitated.

United States Patent Marine et al.

[4 Nov. 11, 1975 PIVOTAL ROTARY SCREEN SUPPORT AND CONTINUOUS DRIVE THEREFOR [75] Inventors: Thomas Marino, Totowa Boro.;

John Kreeft, Wyckoff; Peter Stanislaw, Stockhom, all of NJ.

[73] Assignee: Morrison Machine Co., Paterson,

[22] Filed: Oct. 11, 1973 [21] Appl. No.: 405,264

[52] US. Cl. 101/115; 101/116; 101/182 [51] Int. Cl. B41F 15/10; B41F 5/18 [58] Field of Search 101/115,116,118,127.1, 101/128.l, 178,182

[56] References Cited UNITED STATES PATENTS 1,330,793 2/1920 Friess 101/178 UX 2,170,286 8/1939 I-lintze et al. 101/178 2,762,295 9/1911 Varga et al. 101/178 UX 2,809,581 10/1957 Clem 101/178 2,821,913 2/1958 J0hnson.. 101/178 2,869,459 1/1959 Bohme 101/178 X 3,026,798 3/1962 Frostad... 101/178 X 3,098,434 7/1963 Lime 101/178 3,313,232 4/1967 Van Der Winden 101/118 3,456,584 7/1969 Moskowitz 101/115 X 3,774,533 11/1973 Ichinose 101/119 [57] ABSTRACT A screen printing machine is provided which includes a frame, a backing member supported by the frame, and at least one rotary screen assembly carried by the frame. Each rotary screen assembly is pivotally supported by the frame and includes an inner elongated support member, an outer hollow screen rotatably supported about the inner elongated support member for rotation thereabout, and an elongated applicator, which may be a conventional squeegee, which engages the inner surface of the hollow screen and which is supported by the inner elongated support member located within the screen. A first drive is provided which is operatively connected with the backing member and the rotary screen assembly for rotating the backing member and the outer hollow screen.

In accordance with the invention, a second drive is provided for rotating the hollow screen independently of the first drive and the backing member when the screen assembly is moved away from printing engagement with the backing member about the pivoted support. The second drive is selectively operable upon deactivation of the first drive so that the hollow screen of the rotary screen assembly can be rotated after the first drive is deactivated and rotation of the backing member has stopped. In this manner, ink carried in the rotary screen assembly will be continually agitated.

21 Claims, 5 Drawing Figures US. Patent Nov. 11, 1975 Sheet10f4 3,918,362

FIG. 1

US. Patent N0v.11,1975 Sheet2of4 3,918,362

#mQ d wmw mmw kON 09 m0 U.S. Patent Nov. 11, 1975 Sheet 3 of4 3,918,362

VARIABLE CLUTCH SPEED 260' I DEVICE 253 q: DRUM 266 g} 272 3: sum? 1 5 CLUTCH m ROTARY SCREEN ASSEMBLY MOTOR 2 PIVOTAL ROTARY SCREEN SUPPORT AND CONTINUOUS DRIVE THEREFOR BACKGROUND OF THE INVENTION Rotary screen printing machines are well known and typically include a frame, a backing means supported by the frame, and at least one, and usually a plurality, of rotary screen assemblies which are carried by the frame in close proximity with respect to the backing means. Typically, each rotary screen assembly includes an inner elongated support member, an outer hollow patterned screen supported about the inner elongated support member for rotation thereabout, and an elongated applicator, such as a conventional squeegee, which is supported on the inner elongated support member and engages the inner surface of the screen to press coloring paste or ink through the perforated pattern thereof as the fabric being printed is passed between the respective hollow screen and the backing means. In a rotary type screen printing machine, the baccking means comprises a large drum and the plurality of rotary screen assemblies are supported circumferentially thereabout. In a flat bed screen printing machine, it is normal practice to provide the rotary screen assemblies in a common plane with each screenassembly being provided with a cooperating back-up roller associated therewith.

In the above-described types of machines, drive means are provided which drive the backing means (usually a large rotary drum) and the rotating screens of each assembly in response to rotation of the backing means. In order to effect such rotation, screen gear means are provided at one end of each of said rotary screen assemblies and a main gear, commonly referred to as a sun gear, is provided at one end of the backing means. The individual screen gears of the rotary screen assemblies engage the sun gear of the backing means so that upon rotation of the backingmeans and its sun gear, simultaneous rotation of the screen gears and said rotary screens connected thereto is effected. When the drive means is deactivated, this causes stoppage of the backing means and its associated sun gear and thus stoppage of rotation of the screen gears and associated screens.

Such screen printing machines which carry an ink or color paste supply in the screens are complicated in design and structure and require shutdown for maintenance and repair'in order to keep operating efficiently. Furthermore, operation of these machines is often suspended so that the machines can be resupplied with fabric to be imprinted upon. If the machine is promptly 'started up after such shut-downs, the ink or color paste will tend not to drip through the bottom of the screen and efficient operation of the machine can be maintained and a quality product produced. However, at times, prompt resumption of operation of the machine is not always possible and the machine including the ink or paste supply may remain idle for a significant length of time. The result is that the ink or paste supply tends to drip through the screen during the shut-down period. In such case, when operation is resumed, the bottom of all screens must be wiped off and a low quality printed product is produced wherein the pattern printed on the fabric will include unsightly flaws or other undesirable characteristics until the excess ink or coloring paste is completely cleaned off.

SUMMARY OF THE INVENTION In accordance with the present invention, a screen printing machine is provided with improved mechanisms which make it possible to continue rotation of the rotary screens evenafter rotation of the backing means, such as a large rotray drum, is halted. In this manner, the ink or paste carried in the rotary screen assemblies is continually agitated and will not drip through the screen even after the rotation of the backing means is stopped.

The screen printing machine of the invention comprises a frame, a backing means, such as a large rotary drum, supported by the frame, at least one rotary screen assembly carried by the frame, said assembly including a rotatable screen; first drive means operatively associated with the backing means and the rotatable screen of said rotary screen assembly, for rotating said rotatable screen and said backing means, and second drive means for rotating said rotatable screen independently of said first drive means and said backing means. The second drive means is selectively operable upon deactivation of said first drive means.

A preferred embodiment of this aspect of the invention comprises a first drive means which comprises main motor means, a first linkage means interconnecting said main motor means and said backing means, a second linkage means interconnecting said main motor means and said rotary screen assemblies, and first clutch means interposed within said second linkage means. The second drive means comprises a supplementary motor and associated second clutch means for selectively rotating a hollow screen of at least one rotary screen assembly.

In oneaspect of the present invention, after the first drive means is deactivated or shut down, the screen printing machine of the invention includes means for moving one end of each of said rotary screen assemblies out away from the backing means. This action allows for the initiation of the second drive means which drives or rotates the rotatable screens of said assemblies independently of the first drive means and permits the screens to rotate without printing the halted fabric. However, it will be appreciated that the apparatus of the invention may also include means for moving both ends of each of said rotary screen assemblies out away from the backing means. An example of such means may comprise conventional piston-cylinder means. In this embodiment, means are provided for driving or rotating said rotatable screens when said screens are disposed away from said backing means.

In another embodiment of the invention, the screen printing machine of the invention includes means for moving one end of each of said rotary screen assemblies out away from the backing means as described herein. The other end of each of said rotary screen assemblies may also be moved slightly away from said backing means, for example, by use of conventional poston-cylinder means, while keeping 'said end (via its gear teeth) in engagement with said backing means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a screen printing machine constructed in accordance with the teachings of the present invention;

FIG. 2 is a side view, partially in section, of a portion of the apparatus of the present invention shown in FIG.

FIG. 3 is a cross-sectional view of the portion of the apparatus of the instant invention shown in FIG. 2, taken along lines 3-3 of FIG. 2;

FIG. 4 is a side view, partially in section, of another portion of the apparatus of the present invention as illustrated in FIG. 1;

FIG. 5 is a schematic illustration of the apparatus in accordance with the present invention as shown in FIG. 1 including drive means for operating such apparatus.

DETAILED DESCRIPTION OF THE DRAWINGS Turning to the Figures, there is shown in FIG. 1 a screen printing machine broadly designated 10. The machine includes a frame 12 having side legs 14 and 16 which are provided at their respective upper ends thereof with circular end blocks 16 and 18, respectively. Journaled for rotation between the end blocks 16 and 18 is backing drum 20. Supported circumferentially about the drum 20 by support arrangements broadly designated 22 which project out from the respective circular end blocks 16 and 18 are a plurality of identical rotary screen assemblies 24. The construction of the rotary assemblies 24 will be presented in further detail, but sufficient for present understanding, it is well known that such rotary screen assemblies include a hollow screen 26 having finely apertured patterns through which ink or coloring paste is forced by an internal squeegee arrangement so as to print corresponding patterns on the material 28 passing between the backing drum 20 and the rotary screen assemblies 24. In this connection, a large gear 30 is freely mounted for rotation on the same shaft (not shown) upon which the back-up drum 20 rotates, said gear 30 being free to rotate independently of the drum 20. The teeth of gear 30 engage corresponding teeth on screen gears 32 associated with each rotary assembly 24, whereby rotation of the gear 30 causes corresponding rotation (but in opposite direction) of the screen 26. A detailed description of the operations of these elements will be set out hereinafter in the discussion of FIG. 5.

It will be appreciated from the above discussion that the invention hereof is being illustrated in the environment of a rotary screen printing machine, that is one which includes the large rotating back-drum 20 about which are circumferentially spaced the rotary screen drum assemblies 24. Such a printing machine is described in detail in copending application Ser. No. 326,396 filed Jan. 24, 1973, now abandoned and continuation-in-part Ser. No. 537,649, filed Dec. 31, 1974, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference thereto. However, the invention hereof is not to be deemed limited to such environment since as it will become apparent, the principles hereof will be applicable to a conventional flat bed screen printing machine in which the plurality of rotary screen assemblies are located in the same plane and each is provided with an individually associated back up roller.

As seen in copending application Ser. No. 326,396, each rotary screen assembly 24 includes an inner elongated support member provided at each end with a support block. Extending from opposite ends of the inner elongated support member are first and second hollow shaft members 40 and 42 respectively, shown in FIGS.

l and 5 hereof. The hollow screen 26 is freely rotatably supported with respect to the inner elongated support member by being carried by a pair of circular end plates 48 only one of which is shown in FIG. 5 of copending application Ser. No. 326,396) which are freely rotatable with respect to the associated shaft member 40 (or 42 at the other end) with the aid of ball bearings (not shown).

The inner elongated support member supports an elongated applicator which is a squeegee the edge of which engages the inner surface of the screen 26 to force ink through the patterned regions provided therethrough. A complete description of the squeegee and its associated components is disclosed in copending application Ser. No. 326,396.

As is well known, the orientation is such that the point of engagement of the squeegee with respect to the inner surface of the screen 26 is on the radius of the back-up drum 20. In other words, the squeegee lies perpendicular to the flow path of the fabric 28 passing between the screen 26 and the back-up roller 20.

Referring to FIGS. 1 together with FIG. 2 to 4, it is seen that for each rotary screen assembly 24, the frame includes a pair of outstanding projections 86 and 88, respectively. Slidably mounted on the projections 86 and 88 are carriages or saddles 90 and 92, respectively, (sadddle 90 being shown in FIG. 1 and saddles 90 and 92 being shown in FIGS. 2 and 4 respectively), which include forwardly extending lead screws 94 which engage internally threaded passageways provided in outstanding studs 96 provided on the projections 86 and 88, respectively. On the lead screws 94 are hand wheels 98 which may be rotated to cause the saddles 90 and 92 to travel inwardly or outwardly on the projections 86 and 88, with respect to the back-up drum 20 in a manner as will be described hereinafter.

As best seen in FIGS. 2 and 4, the carriages 90 and 92 include upstanding wall portions 100, 102 which define a bed for rotatable shaft holder 104 (on carriage 92) and shaft holder 106 (on carriage 90) which receive and carry the respective shaft members 40 and 42 which extend from opposite ends of the respective rotary screen assembly 24.

The holder means 106 (shown in FIG. 2) may include means for rotating the same. For effecting rotation, an arm is secured to wall portion 102. Arm 105 has ball thrust bearings at the end thereof through which passes an externally threaded adjusting screw 110. Secured on the front face of the holder 106, there is a horseshoe-shaped plate 112 having an extension 114, the teeth 116 of which are engaged by the teeth of the adjusting screw in a worm and gear fashion. Rotation of the screw 110 causes corresponding rotation of holder means 106, which rotates the shaft member 40 of screen assembly 24 to permit anugular adjustment of the squeegee from a location outside of screeen 26.

As noted previously, the instant invention includes means for continuing to rotate the hollow screen of the rotary screen assemblies after rotation of the back-up drum is stopped. To this end, the screen printing machine of the invention includes first drive means (which will be described in detail with respect to FIG. 5) for rotating the back-up drum 20 and the hollow screens of the rotary screen assemblies 24 and second drive means for rotating the hollow screens of the rotary screen assemblies 24 after the first drive means is deactivated and rotation of the back-up drum is halted. Furthermore, the screen printing machine of the invention includes special base means for supporting carriage means 92 at each end of the rotary screen assemblies so as to allow the end of the rotary screen assemblies away from the large gear 30 and the screen gear 32 to be moved away from the back-up drum after the first drive means is deactivated and thereby allow for activation of the second drive means for independently rotating the hollow screens of the screen assemblies 24 without printing the halted fabric.

A detailed description of the preferred embodiment of the improvements of the instant invention for carrying out the above sequence of events follows.

In FIG. 4 there is shown the projection 88 and associated carriage structure carried thereby which are positioned at end 196 of the machine shown in FIG. 1, that is at the end away from large gear 30 and screen gear 32.

As shown, the carriage 92 is mounted on and supported by a movable base section generally referred to by the numeral 199, which comprises an upper base portion 200 and a lower base portion 202. The lower base portion 202 may comprise an L-shaped member including horizontal leg 205 and vertical leg 206. The vertical leg 206 of said lower base portion encloses a ball bearing 207 through which the lead screw 94, is rotatably fixed. The fixed projection 96 has an internally threaded aperture through which the lead screw 94 may be rotatably fixed. As can now be seen, rotation of the hand wheel 98 and the lead screw 94 will cause the base 199 and carriage 92 (and 90, FIG. 2) to move and thus the position thereof can be adjusted by the operator. It will be appreciated, however, once the position of the carriage 92 (and 90) is selected, the lower base portion 202 becomes effectively fixed in space relative to the projection 88 by virtue of the rigid link of vertical leg 206, lead screw 94 and projection 96.

The upper base portion 200 may take the form of an L-shaped member at least a portion of the horizontal leg 208 of which is slidably mounted on said horizontal leg 205 of the lower base portion 202.

The carriage 92 is secured to horizontal leg 208 by conventional means, such as by means of depending stud 210 and ring washer 212, as shown.

As indicated, the upper base portion 200 which supports carriage 92 is designed to slide on lower base portion 202, and thus move holding means 104 and shaft member 42 of said rotary screen assembly 24 from a position where shaft member 42 and holding means 104, and screen 26 are in close proximity to back-up drum 20 (referred to as the in position) away from the back-up drum 20 to a position (as indicated by the phantom lines 300 in FIG. 4) where shaft member 42 and holder means 104 and screen 26 are away from the drum 20 (referred to as the out position).

Member 202 is also provided with holder moving means generally referred to by the number 220 which may take the form of any conventional mechanical, hydraulic, pneumatic or electrical means whichwill cause desired sliding movement of said upper base portion 200 along said lower base portion 202. As shown, holder moving means 220 comprises a pneumatically or hydraulically operated piston-cylinder arrangement which includes cylinder 222 secured to under surface of said lower base portion 202, and piston 224 disposed within cylinder 222. Piston rod 226 is secured at a first end to piston 224 and is secured at a second end to vertical leg 228 of said upper base portion 200 by conventional means, such as by screw and nut means as shown. Fluid conveying means 230, and 231 in the form of two pipes or similar conduit means include ends portions 232 and 234 which are connected to the interior of cylinder 222 on opposite sides of the piston 224. End portion 232 of conduit 230 is disposed so as to communicate with that portion of the interior of the cylinder 222 in front of piston 224, and end portion 234 of conduit 231 is disposed so as to communicate with that portion of the cylinder 222 in back of said piston 224. The other end of said conduits 230, and 231 are in communication with a fluid supply such as an air or hydraulic fluid supply (not shown for purposes of clarity).

As will be apparent from FIG. 4, movement of piston 224 is effected by feeding fluid into conduits 230 or 231 and into cylinder 222 which will in turn cause corresponding movement of said upper base portion 200 along said lower base portion 202. Such movement will be initiated after rotation of the back-up drum is stopped, as will be further explained hereinafter.

It will be appreciated that when the aforementioned operation takes place and the screen 26 is moved to the out position", the second drive means to be described below can continue to independently rotate the screen 26 to agitate the ink or paste therein without printing on the fabric which has been stopped when the first drive means is deactivated.

Referring now to FIGS. 2 and 3, there is shown the projection 86 and its associated carriage structure which are disposed at end 195 of the screen printing machine shown in FIG. 1, that is at the end where the large gear 30 and the screen gear 32 are positioned. Like the carriage 92, the carriage 90 comprises an upper base portion 232a and a lower base portion 234a.

The lower base portion 234a may comprise an L- shaped member including horizontal leg 236 and vertical leg 238.

The vertical leg 238 of said lower base portion 234a encloses a ball bearing 207 through which the lead screw 94 may be rotatab ly fixed. As can now be seen, rotation of the hand wheel 98 and the lead screw 94 will cause the entire base and carriage 90 to move and thus the position thereof can be adjusted by the operator.

The upper base portion 232a may take the form of an L-shaped member at least a portion of horizontal leg 240 of which is secured to said horizontal leg 236 of said lower base portion 234a by conventional means, such as by screws 242, as shown. Thus, at this end of the machine, there is no sliding motion between the upper and lower base portions 232a, 234a respectively. However, holder means 106 is pivotally mounted with respect to upper base portion 232a by swivel means 244 which may take the form of depending stud 245 and lock ring 248.

The swivel means 244 allows holding means 106 which carries shaft member 40 of the rotary screen assembly 24 to swivel on the upper base portion 232a as the carriage 92 and upper base portion 200 on projection 88 are slid away from the back-up drum 20 at the far end 196 of the machine 10.

In cross-section, upper base portion 232a is generally U-shaped and has depending side legs 281 and 283 provided with gibs or hearing surfaces 281a and 283a which engage the undersurface of a transverse flange portion 287 of the projection 86. In this manner, the carriage is effectively trapped on the projection 86.

The back-up drum 20 and the rotary screen assemblies 24 are preferably driven by drive means as schematically shown in FIG. 5.

FIG. illustrates one rotary screen assembly 24. However, it will be appreciated that a typical rotary screen printing machine will include a plurality of such rotary screen assemblies positioned about back-up drum 20, each of said assemblies having a screen gear 32, at end 195 therof, in engagement with large gear 30 (as shown in FIG. 1). Each screen 26 is linked to its respective screen gear 32 for rotation therewith. As disclosed, for example, in copending application Ser. No. 326,396, this can be preferably accomplished employing one or more linking pins 33 joining the screen gear 32 and the end plate 48.

As shown in FIG. 5, back-up drum is fixedly secured to shaft 252. Large gear is positioned on end 253 of shaft 252 in a manner so as to float or freely rotate about said shaft 252 independently of back-up drum 20. As noted, screen gear 32 is linked to screen 26 of rotary screen assembly 24, and teeth of screen gear 32 engage corresponding teeth on large gear 30, whereby rotation of gear 30 causes corresponding rotation of screen gear 32 and thus rotation of screen 26 of the rotary screen assembly 24.

First drive means indicated generally by the numeral 250 are operatively connected to and employed to drive back-up drum 20 and screen 26 of rotary screen assembly 24. First drive means 250 include motor means 262 and a first linkage means such as a conventional pulley system 257 which interconnects output shaft 256 of motor means 262 to end 254 of shaft 252 upon which back-up drum 20 is fixedly secured.

Driven shaft 258, which is independent of said backup drum 20, is operatively connected by means of second linkage means such as conventional pulley arrangement 259 to the output shaft 256 and motor means 262. Drive gear 260, the teeth of which engage corresponding teeth in large gear 30, is fixedly secured to shaft portion 258a, as shown. As noted previously, large gear 30 is freely floating on shaft end portion 253 and is in effect the sun gear by which all of the planetary screen gears 32 (attached to screens 26) may be rotated.

Although driven shafts 258 and 252 and output shaft 256 are preferably linked to the same motor means 262, it will be apparent that if desired, separate motor means may be employed to drive driven shafts 252 and 258.

Conventional clutch means 264 is carried by and operatively interconnects portions 258a and 258b of driven shaft 258 to permit simultaneous rotation of said shaft portions 258a and 258b only when rotation of drum 20 is desired. The reason for this arrangement will become further apparent. The clutch means 264 is preferably an electric clutch which includes a circular magnet that brings the clutch plates together when energized. An example of such an electric clutch is the ROTO-SPROKET Electric Clutch manufactured by Stearns Elec. Corp. However, other conventional clutches may be employed as will be apparent to those skilled in the art.

Second drive means generally referred to by the numeral 266 are provided for causing rotation of screen 26 of rotary screen assembly 24 when the first drive means including motor means 262 is deactivated. Second drive means 266 comprise supplementary motor means 268, and conventional over-running clutch means 270 operatively connected with motor means 268 through drive shaft 272. The output shaft 274 interconnects clutch means 270 with screen gear 32. An example of such an over-running clutch suitable for use herein is a FORMSPRAG over-running clutch distributed by General Chain and Belt Co., NY.

Thus, when the first drive means 250 is activated to cause rotation of back-up drum 20 and drive gear 260, which in turn causes rotation of large gear 30 and rotation of screen gears 32 (to cause rotation of screens 26 of rotary screen assembly 24) over-running clutch 270 will effectively disconnect shaft 274 from supplementary motor means 268. However, when the first drive means 250 including motor means 262 is deactivated, supplementary motor means 268 can be activated to drive shafts 272,274 and screen gears 32 to independently rotate screens 26. Of course, when the screens 26 are driven by supplementary motor 268, sun gear 30 and drive gear 260 will of necessity, be rotated. However, in this situation, the aforementioned electric clutch 264 will provide the necessary disconnect functions.

It will also be appreciated that once the sun gear 30 is rotated by supplementary motor means 268, all planetary gears 32 (and screens 26) will be rotated thus requiring only one supplementary motor.

In accordance with the present invention, the supplementary motor means 268 is to be activated when the motor means 262 is deactivated and the rotary screen assembly is moved to its so-called out position. In order to coordinate the independent movement of the rotary screens 26 with the overall operation of the machine, and the movement of the screen assemblies 24 from between their in and out positions, the vertical leg 228 (FIG. 4) carries a follower rod 284 having a pair of camming surface 286 and 288 which coact with limit switches 280 and 282 as follows.

As shown in FIGS. 1 and 4, when the holder means 104 and the shaft 42 of rotary screen assembly 24 carried thereon, is in its in position" in close proximity to back-up drum 20, limit switch 280 is moved to its closed position by camming surface 286 which in turn allows activation of said first drive means 250 and thus main motor means 262. In this situation, the machine is printing. However, when the holder means 104 and the shaft 42 of the rotary screen assembly are moved via piston cylinder arrangement 220 to their out position, camming surface 286 is moved out of contact from limit switch 280 to deactivate main motor 262 and camming surface 288 is brought into contact with limit switch 282 to close the same and allow for initiation of the second drive means 266 and the supplementary motor means 268.

In such situation, the machine is effectively turned off, the fabric has stopped moving, but the screens 26 may thus be slowly rotated to continuously agitate the ink supply therein. Of course, because the screen assembly has been moved to its out position away from the fabric, no printing can take place.

When it is desired to reinitiate the printing operation, the piston cylinder arrangement is operated to move the screen assemblies to their in, printing position. In this case, camming surface 288 will be removed from operative association with limit switch 282, thereby deactivating supplementary motor means 268; and camming surface 286 will operate limit switch 280 to reactivate the main motor 262 and reinitiate printing.

With respect to FIG. 5, it will be seen that the first drive means 250 may optionally include a variable speed device 289 for varying the speed of rotation of the rotatable screens 26 with respect to the speed of rotation of the back-up drum 20. Such an arrangement is described in the copending patent application Ser, No. 405,418, filed Oct. 11, 1973 entitled Rotary Screen Printing Machine With Means For Rotating Sun Gear Independently of Main Drum. in the name of Marino, Kreeft and Stanislaw and assigned to the assignee of the present invention and filed concurrently therewith.

The above has been a description of the screen printing machine of the invention which includes means for continually rotating the rotary screens thereof after rotation of the back-up drum is stopped, in order to continue agitation of the ink or color paste carried in the rotary screen assemblies and thereby prevent dripping of such ink or paste through the screen during such stoppage, and without undesirable and unintended printing.

Although this invention has been described with respect to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred, therefore, that the scope of the invention be limited, not by the specific disclosure herein, only by the appended claims.

What is claimed is: 1. A screen printing machine comprising:

a frame: a backing member supported by said frame; at least one rotary screen assembly rotatably carried by said frame and adjustably positionable between printingengagement'and away from printing engagement with said backing member, said assembly including a rotatable screen and means for pivotally supporting said screen assembly at a point beyond one end of said screen; moving means for moving said rotary screen assembly away from printing engagement with said backing member about said supporting means; means for rotating said rotatable screen when said rotary screen assembly is in printing engagement and is away from printing engagement with said backing member. 2. The screen printing machine according to claim 1, wherein said backing member comprises a rotary drum and wherein there is provided a plurality of said rotary screen assemblies distributed circumferentially about said rotary drum, said rotary drum being disposed on and rotatable with a first shaft, a sun gear rotatably disposed on said first shaft for rotation independent of said rotary drum, and each of said rotary screen assemblies including a planetary gear for engaging said sun gear when said rotary screen assemblies are in printing engagement with said drum, and said means for rotating said rotatable screen when each said rotary screen assembly is away from printing engagement with said backing member, includes second drive means operatively connected to said planetary gears to rotate the rotatable screen of each rotary screen assembly when said rotary screen assemblies are away from printing engagement with said drum.

3. The screen printing machine of claim 1, wherein said means for rotating said rotatable screen when said rotary screen assembly is in printing engagement with said backing member comprises first drive means operatively connected to said rotatable screen.

4. The screen printing machine of claim 3 wherein said means for rotating said rotatable screen when said rotary screen assembly is away from printing engagement with said backing member, comprises second drive means operatively connected to said rotatable screen.

5. The screen printing machine of claim 4 further including means for deactivating said first drive means when said rotary screen assembly is away from printing engagement with said backing member.

6. The screen printing machine according to claim 4, wherein said backing member comprises a rotary drum and wherein there is provided a plurality of said rotary screen assemblies distributed circumferentially about said rotary drum, said rotary drum being disposed on and rotatable with a first shaft, a sun gear rotatably disposed on said first shaft for rotation independent of said rotary drum, and each of said rotary screen assemblies including a planetary gear for engaging said sun gear when said rotary screen assemblies are in printing engagement with said drum, and said means for rotating said rotatable screen when each said rotary screen assembly is away from printing engagement with said backing member includes second drive means operatively connected to said planetary gears to rotate the rotatable screen of each rotary screen assembly when said rotary screen assemblies are away from printing engagement with said drum 7. The screen printing machine according to claim 6 wherein said first drive means comprises a main motor, first linkage means connecting said main motor to said rotary drum for rotatably driving said drum, a drive gear, said drive gear being operatively engaged with said sun gear means, and second linkage including means for selectively connecting said main motor to said drive gear for driving said sun gear and thereby driving said planetary gears and said rotary screens.

8. The screen printing machine according to claim 7 further including a first clutch intermediate said main motor and said drive gear, a second clutch intermediate said supplementary motor and said planetary gears, and control means causing said first clutch means to be engaged and said second clutch means to be disengaged when said first drive means including said main motor is activated and said second drive means is deactivated, and causing said second clutch means to be engaged and said first clutch means to be disengaged when said second drive means is activated and said first drive means is deactivated.

9. The screen printing machine according to claim 7 wherein said second drive means comprises means for selectively driving at least one of said planetary gears.

10. The screen printing machine according to claim 9 wherein said driving means comprises a single motor for driving a plurality of said rotatable screens.

11. The screen printing machine according to claim 5 further including control means for activating said second drive means to rotate said screens after-said first drive means is deactivated.

12. The screen printing machine according to claim 1 1 wherein said control means includes automatic control means responsive to movement of each said rotary screen assembly toward said backing member for deactivating said second drive means and for activating said first drive means.

13. The screen printing machine according to claim 12 wherein each of said rotary screen assemblies comprises first and second end shaft members extending to opposite locations disposed outside of each said rotatable screen, and further comprising first and second holder means rotatably supporting said end shaft mem bers, respectively, said second holder means being disposed at said end away from said planetary gears.

14. The screen printing machine as defined in claim 13 wherein said moving means comprises holder moving means for moving said second holder means and said second end shaft member of each said rotary screen assembly between first and second positions, said first position comprising that position where said rotary screen assemblies are in printing engagement with said backing member, and said second position comprising that position where said rotatable screen assemblies are away from printing engagement with said backing member.

15. The screen printing machine in accordance with claim 14 wherein said holder moving means comprises a piston-cylinder assembly operatively connected to said second holder means for moving said second holder means.

16. The screen printing machine of claim 14, wherein said frame further includes first and second carriages slidably supporting said first and second holder means relative to said backing member, and said second carriage comprising a lower base section mounted on an upper base section, said second holder means being connected to said upper base section, for relative movement of said upper base section with respect to said lower base section toward and away from said backing member.

17. The screen printing machine in accordance with claim 16 wherein said first carriage comprises a lower base section and an upper base section mounted on said lower base section, and means for rigidly connecting said lower base section to said upper base section, said first carriage including said supporting means for pivoting said first carriage as said second holder means, said second carriage and said upper base section of said second carriage are moved toward or away from said rotary drum.

18. The screen printing machine in accordance with claim 17 wherein said holder moving means comprises a piston cylinder assembly operatively connected to said upper base portion of said second carriage.

19. The screen printing machine according to claim 14 wherein said automatic control means includes a follower member operatively connected to each said rotary screen assembly for movement in proportion to movement of each said rotary screen assembly, first and second cam surfaces operatively connected to said follower member, and a pair of switches disposed for engagement with respective ones of said cam surfaces for operation thereby.

20. The screen printing machine as defined in claim 19 wherein said switches are responsive to'the movement of said second holder means between its first and second positions for activating said first drive means and deactivating said second drive means when said second end shaft portion of each said rotary screen assembly is in said first position and for activating said second drive means and deactivating said first drive means when said second end shaft portion of each said rotary screen assembly is in said second position away from said rotary drum, and said follower member is connected to said piston of said piston-cylinder assembly which is responsive to motion of said second holder means for controlling said switches.

21. The screen printing machine as defined in claim 20 wherein said switches comprise first and second limit switches, said first drive means being responsive to said first limit switch and said second drive means being responsive to said second limit switch, said first cam surface being in contact with said first switch to activate said first switch when said second holder means is in its first position, and said second c am surface being in contact with said second limit switch to activate said second limit switch when said second holder means is in its second position. 

1. A screen printing machine comprising: a frame: a backing member supported by said frame; at least one rotary screen assembly rotatably carried by said frame and adjustably positionable between printing engagement and away from printing engagement with said backing member, said assembly including a rotatable screen and means for pivotally supporting said screen assembly at a point beyond one end of said screen; moving means for moving said rotary screen assembly away from printing engagement with said backing member about said supporting means; means for rotating said rotatable screen when said rotary screen assembly is in printing engagement and is away from printing engagement with said backing member.
 2. The screen printing machine according to claim 1, wherein said backinG member comprises a rotary drum and wherein there is provided a plurality of said rotary screen assemblies distributed circumferentially about said rotary drum, said rotary drum being disposed on and rotatable with a first shaft, a sun gear rotatably disposed on said first shaft for rotation independent of said rotary drum, and each of said rotary screen assemblies including a planetary gear for engaging said sun gear when said rotary screen assemblies are in printing engagement with said drum, and said means for rotating said rotatable screen when each said rotary screen assembly is away from printing engagement with said backing member, includes second drive means operatively connected to said planetary gears to rotate the rotatable screen of each rotary screen assembly when said rotary screen assemblies are away from printing engagement with said drum.
 3. The screen printing machine of claim 1, wherein said means for rotating said rotatable screen when said rotary screen assembly is in printing engagement with said backing member comprises first drive means operatively connected to said rotatable screen.
 4. The screen printing machine of claim 3 wherein said means for rotating said rotatable screen when said rotary screen assembly is away from printing engagement with said backing member, comprises second drive means operatively connected to said rotatable screen.
 5. The screen printing machine of claim 4 further including means for deactivating said first drive means when said rotary screen assembly is away from printing engagement with said backing member.
 6. The screen printing machine according to claim 4, wherein said backing member comprises a rotary drum and wherein there is provided a plurality of said rotary screen assemblies distributed circumferentially about said rotary drum, said rotary drum being disposed on and rotatable with a first shaft, a sun gear rotatably disposed on said first shaft for rotation independent of said rotary drum, and each of said rotary screen assemblies including a planetary gear for engaging said sun gear when said rotary screen assemblies are in printing engagement with said drum, and said means for rotating said rotatable screen when each said rotary screen assembly is away from printing engagement with said backing member includes second drive means operatively connected to said planetary gears to rotate the rotatable screen of each rotary screen assembly when said rotary screen assemblies are away from printing engagement with said drum
 7. The screen printing machine according to claim 6 wherein said first drive means comprises a main motor, first linkage means connecting said main motor to said rotary drum for rotatably driving said drum, a drive gear, said drive gear being operatively engaged with said sun gear means, and second linkage including means for selectively connecting said main motor to said drive gear for driving said sun gear and thereby driving said planetary gears and said rotary screens.
 8. The screen printing machine according to claim 7 further including a first clutch intermediate said main motor and said drive gear, a second clutch intermediate said supplementary motor and said planetary gears, and control means causing said first clutch means to be engaged and said second clutch means to be disengaged when said first drive means including said main motor is activated and said second drive means is deactivated, and causing said second clutch means to be engaged and said first clutch means to be disengaged when said second drive means is activated and said first drive means is deactivated.
 9. The screen printing machine according to claim 7 wherein said second drive means comprises means for selectively driving at least one of said planetary gears.
 10. The screen printing machine according to claim 9 wherein said driving means comprises a single motor for driving a plurality of said rotatable screens.
 11. The screen printing machine according to claim 5 further including control means for activating said second drive means to rotate said screens after said first drive means is deactivated.
 12. The screen printing machine according to claim 11 wherein said control means includes automatic control means responsive to movement of each said rotary screen assembly toward said backing member for deactivating said second drive means and for activating said first drive means.
 13. The screen printing machine according to claim 12 wherein each of said rotary screen assemblies comprises first and second end shaft members extending to opposite locations disposed outside of each said rotatable screen, and further comprising first and second holder means rotatably supporting said end shaft members, respectively, said second holder means being disposed at said end away from said planetary gears.
 14. The screen printing machine as defined in claim 13 wherein said moving means comprises holder moving means for moving said second holder means and said second end shaft member of each said rotary screen assembly between first and second positions, said first position comprising that position where said rotary screen assemblies are in printing engagement with said backing member, and said second position comprising that position where said rotatable screen assemblies are away from printing engagement with said backing member.
 15. The screen printing machine in accordance with claim 14 wherein said holder moving means comprises a piston-cylinder assembly operatively connected to said second holder means for moving said second holder means.
 16. The screen printing machine of claim 14, wherein said frame further includes first and second carriages slidably supporting said first and second holder means relative to said backing member, and said second carriage comprising a lower base section mounted on an upper base section, said second holder means being connected to said upper base section, for relative movement of said upper base section with respect to said lower base section toward and away from said backing member.
 17. The screen printing machine in accordance with claim 16 wherein said first carriage comprises a lower base section and an upper base section mounted on said lower base section, and means for rigidly connecting said lower base section to said upper base section, said first carriage including said supporting means for pivoting said first carriage as said second holder means, said second carriage and said upper base section of said second carriage are moved toward or away from said rotary drum.
 18. The screen printing machine in accordance with claim 17 wherein said holder moving means comprises a piston cylinder assembly operatively connected to said upper base portion of said second carriage.
 19. The screen printing machine according to claim 14 wherein said automatic control means includes a follower member operatively connected to each said rotary screen assembly for movement in proportion to movement of each said rotary screen assembly, first and second cam surfaces operatively connected to said follower member, and a pair of switches disposed for engagement with respective ones of said cam surfaces for operation thereby.
 20. The screen printing machine as defined in claim 19 wherein said switches are responsive to the movement of said second holder means between its first and second positions for activating said first drive means and deactivating said second drive means when said second end shaft portion of each said rotary screen assembly is in said first position and for activating said second drive means and deactivating said first drive means when said second end shaft portion of each said rotary screen assembly is in said second position away from said rotary drum, and said follower member is connected to said piston of said piston-cylinder assembly which is responsive to motion of said second holder means for controlling said switches.
 21. The screen printing machine as defined in claim 20 wherein said switches comprise first and second limit switches, said first drive means being responsive to said first limit switch and said second drive means being responsive to said second limit switch, said first cam surface being in contact with said first switch to activate said first switch when said second holder means is in its first position, and said second cam surface being in contact with said second limit switch to activate said second limit switch when said second holder means is in its second position. 